Double acting pump



Aug. 26, 1941- H. P. ANDERSON ETAL DOUBLE ACTING PUMP Filed May 16, 1940 2 Sheets-Sheet l /I/ ill 00% \1 III. v

INVENTORS.

' BY Fe 50/64 4. do sroA/E A I Aug. 26, 1941. H, P. ANDERSON ET AL 2,253,926

DOUBLE ACTING PUMP 7 Filed May 16, 1940 2 Sheets-Sheet 2 INVENTORS. H/QEEY fifi/x/ofeso/v. I BY FEDEEIOK A. /0/// 570/V5 Patented Aug. 26, 1941 UNITED A PATENT OFFICE Harry RAnd'rs on-and i r'ederick L. Detroit, Mich.

i iv l t; ;tq new ant u ifl rqt t i a Pum n e h n sm o us in Pumping li ui of d e n onsi te qi tsfieh as water with relatively small efiort, or heavy liquids or oils requiring greaterefi'ort. The invention also lends it'self very eificiently to pumpingliquids contaminated with solid particles irr suspension, such as grit, abrasives, or metal particles; frequently encoimteredfin hanl' e a t 91 s a i uids-p ,c t

Th P i r b c o th nven n htht de: i n. pi m e an so a ran e nd st ted a t e im nat var ou a l sneak n Seats wi w sl qst i ia lur n asedfimt c rqf pera on: ee sqeiat e .7 A t ect of th rimf f v p the pr ne onz 1 a do e. n p a th as 31 sc e havin a m n m m, working a s an surfaces,- result'ing in' a puniping device of great-- er e fi ie an d ra i i y M Another object resides in the provision oj an intermediate pressure supply chan ber between e, s u e oi s pn l nd e u mate qmt. el ver oi th fl i vb e. pumped with-a o e ue t; e t ne of men: even de ive y afifl; -.,.t

.i nQt e ob ct of cthel nvention esi ;in 9. dee n eap n eghanis th t, ti c a hd conq a o ;;manru ctu Qther objects will: appear hereinafter as the stit w is u s od-1 .l l. .mwi l f n e, t the accompanyi g: dr w gs h ph o a pa t 01 h specifi atiqnilik urei: erence characters refer to similar parts through-f out thjeseveral views in which-, a,

.E e- 1 i n a qn of the nven n showin it mounted in a reservoir or the 1ike;;with; a.por-' tion broken away, and I Fig; 2 i s .a vertical section line 2-2 of Fig.1 showing the piston preparatory to vthe downward stroke, and; 4 L

Fi 3 is a view similar to Fig. 2; with the piston near its lower position,- and; 1 .Fig. 4 is a' transverse sectional view taline 4 4 of Fig. 3, and

' n pon.

I Fig 5 is atrans verse sectionalview taken upon e tFie-Bt I In the drawings hefier ce W 1- !i" ii'r'i a. r i i e ie l tear n meet-me, or chamber 1 andat iteimr y nsiti e e reaa, closure casting 9 provided apertures tor a swea a epi nd. i 0t 2 M29 31: ventiofi lp c e ndth i whiq fi i n odhereinafter to be; described protrudes;

aiviettahmuptn;

into which a pistonor p un'gg 11 extends. The piston .being of a greater length than the bore l5, pa r any xt nas mts the chamber" 1, being adapted to rec'iprcat partian in said chamber and partially in the bore 5 of the casting J3 for th'jintak'e'and discharge of the fiuid'being P mP :f-l- V v. I -Iori zontal ports lfi and 2 are forrfied in the base l 3 iortheinijlow of fluids from the source e n i ith e, d v e s.v rim d and fil it ebleP l .i$, 9 d in the 10593 to clbsle thel-ower end of the bore I5 3 a V Referring more particularly to the piston ll, it

isprovided with an inner bor e {25, having an en- 1 scribed.

" larged counterbored portion 25A lfor ease and cheapness of manufacture, eliminating thejiecessityotgrindingthroughput the entirebore. The

u p r n' epii the her i 'sl edu ie at 25B for a purpose to be hereinafter described.

A secondary piston or plunger 211s adapted to reciprocate within said bore 25 25A and 25B of the piston l "I, having clos'esl'iding contact with the portion designated by the nurnerali i' The piston 21 has a c entral axial fluid passage 29, which cornmunicates the bore S in the base, "the u er; e d iii the P s a l. eale by one end of a'piston rod 3| threadedly mounted there- An stewtmtfl i o d ith i i ton rod 3| for a purpose to be hereinafter de-' let awed m i te at r M dd with horizontal discharge ports 35 and 31, serv-v m to conduct fluid into the chamber 1 or the n n l- 4:5 aerating to v,

heir uppermost positions and the;

shell 5 upon de'scend'in previously described. u I

.il'he Pi t s. ma b ie i i h al i d ee middle external portion for ease'in manufacture,

r defi e c h li qn act arie aeiab i tial lower por-tion'for sealing contact between the 40 t sl t a 'lheupper portion of piston 21 is considerably reduced asshown at 28 forming a shoulder 28a for contacting a shoulder 25c in the bore of pis- Operation I 2,11; will'b noted that the P o s j t t l v. ports 35 and 31- are not in registry.

In coming to this position 'the piston 72 movedgthe distance corresponding to the distance that shoulders 28a and 250 are shown apartin Fig. 3 the two shoulders then abutting, and this 5 is the base casting l3, having an axial bore I5,

two pistons int 1a I] oved upwardly as time".

g stroke of the two pistons" 'e ports 1358 1 37 i e he The upward motion of the pistons thus created a vacuum in the bottom of the chamber l5, permitting atmospheric pressure as well as the weight of the liquid to force liquid into said chamber through the ports is and 2|, as indicated by the arrows in Fig. 2.

As the pistons 11 and 21 rise in chamber 1, they displace a volume of liquid therefrom equal to the volumetric area of the travel of the pistons, pumping the same out the outlet pipe I l.

Upon the descending stroke of the piston rod 3!, the piston 21 will first descend until the nut 33 engages the upper surface of piston H, at which time the ports 35 and 31 will register, as shown in Fig. 3. Thereafter the'two pistons will descend as a unit, closing ports l9 to be out of registry when said inner piston moves in the opposite direction, and a discharge port leading from said large cylinder.

3. A pump comprising a large cylinder, a smaller cylinder mounted in one end thereof provided with a fluid inlet, a hollow outer piston mounted in sealing relation in the smaller cylinder and adapted to reciprocate partially in each cylinder, a hollow inner piston mounted in the hollow outer piston and closed at one end, a piston rod for reciprocating said inner piston, a lost motion connection between said pistons, including an outer shoulder on the inner piston and an inner shoulder on the outer piston and a projection on said piston rod, said piston rod,

' on each stroke, first moving the inner piston and 2| and discharging the fluid that was previously trapped in the lower part of chamber 15, through axial passage 29 of inner piston 21 and out through ports 35 and 31 into the,

chamber I in shell 5, and thence forcing fluid out through discharge pipe ll.

The parts are so designed that 'thevolume of liquid trapped in the lower portion of chamher [5 is greater than the volume displaced by the upward stroke of the pistons, so that some fluid is pumped out of the discharge pipe l l upon movement of the pistons in each direction.

Aside from the specific embodiment of the invention herein shown and described, 'it will be understood that numerous details of the construction may be altered or omitted without departing from the spirit and scope of the invention as disclosed and claimed, and that we do not desire to limit the invention to the exact construction herein set forth.

We \claim: 1. A pump comprising a large cylinder, a smaller cylinder mounted in one end thereofprovided with a fluid inlet, a hollow outer piston mounted in sealing relation in the smaller cylinder some and adapted to reciprocate partially in each cyl inder, a hollow inner piston mounted in the hollow outer piston and closed at one end, a-lost motion connection between said pistons, means for reciprocating said inner piston and'thereby ultimately reciprocatingthe outer piston through said connection, ports in said inner and outer pistons adapted to register for discharging fluid therethrough into the large cylinder when said inner piston has been moved sufficiently in one direction to take up the lost motion between the pistons and adapted to be out of registry when said inner piston moves in'the opposite direction, and a discharge port'leading from said:

large cylinder.

2. A pump comprising a large cylinder; a smaller cylinder mounted in one end thereof provided with a fluid inlet, a hollowouter piston' mounted in sealing relation in the smaller cylinder and adapted to reciprocatepartially'in each cylinder, a hollow inner piston mounted in the hollow outer piston and closed at one end, a

lost motion connection between said pistons,-

means for reciprocating said inner piston, said reciprocating means, on each stroke, first causing the lost motion to be taken up and then causing the connection to become effective to thereafter move the outer piston with'it as a unit during the remainder of said stroke, ports in said, inner and outer pistons adapted to register for discharging fluid therethrough into the large cylinder when said inner piston has been moved sufficiently in one direction to take up the lost motion between thepistons' and adapted sufficiently to take up the lost motion, thus causing the connection to become effective to thereafter move the outer piston with the inner piston during the remainder of said stroke, ports in said inner and outer pistons adapted to register for discharging fluid; therethrough into the large cylinder when said inner piston has been moved sufficiently in one direction to take up the lost motionbetween' the pistons and adapted to be out of registry when said inner piston moves in the opposite direction, and a discharge port leading from said large cylinder.

4. A pump mechanism of the class described comprising a large cylinder having a discharge outlet, a smaller cylinder mounted in one end of said large cylinder and provided with a fluid inlet, a hollow outer pistonmounted in sealing relation in thesznaller' cylinder, adapted toreciprocate partially in-'e'ach cylinder and having ports communicating with the large cynnder; an inner piston mounted inthe hollow outer piston, said inner piston having aflong'itudinal' bore closed at one end, ports passing through the upper end of said inner piston for delivery of fluid from the smaller cylinder through the longitudinal bore of said inner piston to the' bore of the outer piston, means for reciprocating said inner piston, and a lost motion connection between said pistons including anexternal' shoulder on said inner piston at a point sub'stantially below its' ports, an internal shoulder in 'the hollow outer'pi'ston in alignment" with the top of its ports, said'shoulder's' being adapted to'contact each other when thepiston ports are out 1 of registry, a projection on the reciprocating I registry, at which time the projection on thereciprocating means will engage the outer piston and the two pistons will then descend as a unit, closing the inletmeans-in the-smaller cylinder and discharging the trapped liquid through the bore of the inner piston and-through the registering piston ports into the large cylinder, thereby discharging some of-the liquid out of the discharge outlet and, upon the upward'stroke of the inner piston, it first moves'up to place the piston ports out of registry and," when the external shoulder of said inner piston contacts the inner shoulderof the first named piston, the two pistons will continue to move upwardly as a unit, thereby creating a vacuumin the smaller cylinder until the outer piston uncovers the fluid inlet the smaller cylinder, atwhich time liquid in the source of; supply willflow irrto'the smaller from the large cylinder and out through the discharge outlet.

5. A pump mechanism of the class described comprising; a shell having an inner chamber, a top closure for said shell and outlet means leading from said shell, a base afiixed to said shell, a cylindrical bore in said base, inlet means for conducting fluid into said bore,a pistonadapted to reciprocate in said bore, said piston having a central bore formed therein and fluid ports communicating with the shell chamber, an inner piston mounted in said central bore of the first named piston and adapted to partially slide therein and to partially reciprocate with said first named piston, said inner piston having a longitudinal passageway, ports in the upper end of said inner piston connecting with said passageway for delivery of fluid from the cylindrical bore in the base to the bore of the first named piston, means for reciprocating said inner piston, said inner piston having an external shoulder at a point substantially below its ports, an internal shoulder in the bore of said first named piston in alignment with the top of its ports, said shoulders being adapted to contact each other when the piston ports are out of registry, a projection on the reciprocating means adapted to contact the upper surface of the first named piston when the piston ports are in reg istry, whereby, upon the downward stroke of the inner piston it will first descend until the piston.

ports are in registry, at which time the projection on the reciprocating means will engage the upper surface of the first named piston and the two pistons will then descend as a unit, closing the inlet means to the bore in the base and discharging the trapped liquid through the longitudinal passage in said inner piston through the registering piston ports into the shell chamber, thereby discharging some of the liquid out of the outlet means and, upon the upward stroke of the inner piston, it first moves up to place the piston ports out of registry and, when the external shoulder of said inner piston contacts the inner shoulder of the first named piston, the two pistons will continue to move upwardly as a unit, thereby creating a vacuum in the lower bore of the base until the first named piston uncovers the inlet means in the base at which time liquid in the source of supply will flow into the bore of said base, the upward movement of the pistons simultaneously displacing a volume of liquid from the shell chamber and out through the outlet means.

6. A pump mechanism of the class described comprising; a shell having an inner chamber, a top closure for said shell and outlet means leading from said shell, a base afiixed to said shell, a cylindrical bore in said base, inlet means for conducting fiuid into said bore, a piston adapted to reciprocate in said bore, said piston having a central bore formed therein and fluid ports communicalting with the shell chamber, an inner piston mounted in said central bore of the first named piston and adapted to partially slide therein and to reciprocate with said first named piston, said inner piston having a longitudinal passageway, ports in the upper end of said inner piston connecting with said passageway for delivery of fluid from the cylindrical bore in the I base to the bore of the first named piston, a piston rod secured to said inner piston for reciprocating said piston and projecting through said top closure, said inner piston having an external shoulder at a point substantially below its ports, an internal shoulder in the bore of said first named piston in alignment with the top of its ports, said shoulders being adapted to contact each other when the piston ponts are out of re istry, a nut on the piston rod adapted to contact the upper surface of the first named piston when the piston ports are in registry, whereby, upon the downward stroke of the piston rod, the inner piston will first descend until the piston ports are in registryat which time the nut on the piston rod will engage the upper surface of the first named piston and'the two pistons will then descend as a unit, closing the inlet means to the bore in the base and discharging the trapped liquid through the longitudinal passage in said inner piston through the registering piston ports into the shell chamber, thereby discharging some of the liquid out of the outlet means and, upon the upward stroke of the piston rod, the inner piston first moves up to place the piston ports out of registry and, when the external shoulder of the inner piston contacts the inner shoulder of the first named piston, the two pistons will continue to move upwardly as a unit, thereby creating a vacuum in the lower bore of the base until the first named piston uncovers the inlet means in the base at which time liquid- 

